Defect engineered nickel hydroxide nanosheets for advanced pseudocapacitor electrodes

While the past years have witnessed great achievement in pseudocapacitors, the inauguration of electrode materials of high-performance still remains a formidable challenge. Moreover, the capacity and rate capability of the electrode depends largely on its electrical conductivity, which ensures fast charge transfer kinetics in both the grain bulk and grain boundaries. Here, nickel hydroxides with oxygen vacancies are facilely fabricated via a hydrothermal method. The active materials exhibit a high specific capacitance of 3250 F·g−1 and a high areal of capacitance of 14.98 F·cm−2 at 4.6 mA·cm−2. The asymmetric supercapacitor device based on our material delivers a high energy density of ∼ 71.6 Wh·kg−1 and a power density of ∼ 17,300 W·kg−1 and could retain ∼ 95